from the private net development benefits in calculating the total social return 

 to drainage investment. Second, the extra farm output that results from wetlands 

 drainage is valued in prices that include tariff protection and government 

 commodity price support components. These components are transfer payments, and 

 should be netted out from the social return on investment calculations. Third, 

 the yield increases are estimated for the most productive lands and do not 

 represent average farmland productivity. There are other technical difficulties 

 in these calculations; the author makes a convincing case that an irrational pro- 

 conversion bias underlies the proposed development projects. 



62. Craft, B.R. 1983. Louisiana story: the gulf coast wetlands. Pages 262- 

 267 in The yearbook of agriculture. U.S. Department of Agriculture, 

 Washington, DC. 



This paper is similar to ([63]). Craft estimates that losses of Louisiana 

 coastal wetlands total 40 square miles per year. These marshes provide 

 overwintering habitat for migratory waterfowl and for important fur-bearing 

 species such as muskrat, nutria, racoon, otter, and mink. The annual Louisiana 

 fur harvest ($8.5 million in 1982) is greater in value than that of the rest of 

 the U.S. and Canada combined. And from 1976 to 1981, a total of 58,725 

 alligators were harvested in these wetlands. Larval and juvenile forms of 

 finfishes and crustaceans, including such economically significant species as 

 shrimp, blue crab, croaker, menhaden, mullet, and bay anchovy, use the estuaries 

 and marshes before migrating to open sea. In 1982, Louisiana produced 1.6 

 billion pounds of commercial fish, with a combined dockside value of $221 

 million. The State produces 50% (by value) of the U.S. commercial harvest of 

 oysters and crabs. 



Saltwater intrusion kills freshwater marsh plants, in turn destroying the 

 surface vegetative mat and dispersing the organic soils of the freshwater 

 marshes. This leads to conversion of freshwater marshes to open seawater. 

 Various protective measures (weirs, levees, the use of plants for erosion 

 control) could substantially slow the wetland loss. Some economic analysis is 

 needed to estimate the magnitudes of the costs and returns for these preventive 

 measures. 



63. Davis, D.W. 1983. Economic and cultural consequences of land loss in 

 Louisiana. Shore and Beach 51(40) :30-39. 



Louisiana's costal wetlands are being lost at the rate of about 25,000 

 acres per year. There are a variety of causes for the loss of this resource, 

 including channel and canal dredging by man, seawater intrusion, subsidence, and 

 shoreline erosion. The loss of coastal wetlands entails a loss of habitat for 

 such economically significant species as migratory waterfowl and shrimp. In 

 1983, these wetlands still totaled 6.5 million acres. 



64. Leitch, J. A. 1983. Economics of prairie wetland drainage. Transactions 

 of the American Society of Agricultural Engineers 26(5) : 1465-1470. 



This paper analyzes the same data on drainage costs and gross and net 

 returns to drainage investment that was presented in earlier papers by Leitch 

 ([48]), and Leitch and Kerestes ([49]). There were two study areas from which 



49 



